Problem 2. Consider a financial market modeled by a 3 -period binomial tree. Suppose a stock price at time 0 is S0=$40, and u=1.2,d=0.85. The continuously compound interest rate is r=5%. The period is one year and the dividend yield is 0. (c) What is the optimal exercise policy of the American put option? (i.e. Decide whether you should exercise at t=0,1,2 for different stock prices.)